Survey, pathogenicity, cultural and morphological characterisation of Alternaria isolates associated with Alternaria leaf spot of cabbage

Abstract

Cabbage is a profitable vegetable crop in Kerala grown for its compact head formed by the leaves. Among fungal diseases, Alternaria leaf spot caused by A. brassicicola is a noteworthy concern as it effects the crop all over the world. Hence the present study was conducted to determine the incidence of disease and detail studies of cultural and morphological characters of the pathogen. Survey was taken up in three districts of Kerala viz., Trivandrum, Kollam, Idukki and the maximum per cent disease index (57.14%) was recorded in Muthuvankudy regions of Idukki district. Seven isolates recovered from the diseased samples were isolated, purified and pathogenicity was proved. Cultural and Morphological characters of different isolates of Alternaria spp. obtained during the survey were studied and showed that the mycelia were septate and conidia were produced in chains from the conidiophores. Conidia are beakless and consist of both longitudinal and transverse septa.